Community-supported versions of the Haskell Platform on Linux and Unix
These distributions offer the Haskell Platform in their package repositories. You can easily install the Haskell Platform through your distribution's native package manager.
Information for other systems
See also: justhub, for RHEL, CentOS, Scientific Linux, and Fedora support
Download the source tarball for Unix-like systems: here
Get and install GHC 7.6.3 prior to building the platform:
Finally, unpack the Haskell Platform source tarball, and run (possibly with sudo):
./configure make make install
You may pass the --prefix flag to ./configure to change the default install path.
There is also a README file in the tarball with more detailed information on building.